1. Field of the Invention
The present invention relates to a transmitting system, media converter, and transmitting method which allow communication between terminals.
2. Related Art of the Invention
To access the Internet using a terminal with a communication function, DBL. using telephone lines, FTTH using optical fibers, a cable Internet system using coaxial cables, an Internet system utilizing wireless access points, or the like is used. In an Internet system as described above, terminals are linked to a central device, thereby allowing Internet access.
In the Internet system, when terminals accessing the Internet are to communicate with each other, the communication between the terminals is implemented through the central device or a repeater for the central device.
However, the Internet system has the disadvantage that if trouble or the like occurs in the central device or repeater, and the device becomes unable to operate normally, it becomes impossible to establish a link between each terminal and the central device, and that not only Internet access of the terminals but also communication between the terminals becomes impossible.
As measures to ameliorate the disadvantage, Japanese Patent Laid-Open No. 2000-261782 attempts to implement communication between terminals by using a loopback unit. A signal looped back in the loopback unit has a physical layer and a MAC layer in common with an uplink signal except for a frequency, so that the loopback unit is implemented by a simple arrangement with a band-pass filter, frequency converter, and the like.
The entire disclosure of Japanese Patent Laid-Open No. 2000-261782 is incorporated herein by reference in its entirety.
Even with the conventional technique described above, if trouble or the like occurs in a central device or repeater, and the device becomes unable to operate normally, a link between each terminal and the central device may become invalid, and communication between the terminals may become impossible.
More specifically, the conventional technique has the problem that if, for example, an abnormality occurs in the central device or repeater, and it becomes impossible to establish a link between the central device or repeater and each terminal, communication between the terminals may become impossible.
The present invention has been made in consideration of the above-described problem, and has its object to provide a transmitting system, media converter, and transmitting method which allow communication between terminals even when, for example, it becomes impossible to establish a link between a central device or repeater and each terminal.